Combining Geometries and Descriptions A shape grammar plug-in for Grasshopper

Abstract

A persistent challenge to the more widespread use of shape grammars in architectural research is the creation of rules and rule sets for application in design contexts, while leaving space for design creativity despite the limitations of a rule-based system. A hybrid of associative and rule-based approaches may alleviate this. We present one such development, a Grasshopper shape grammar plug-in that embeds a rule-based approach within a parametric modelling environment. It supports shape emergence, visual enumeration of rule application results, and the parametric definition of shapes and shape rules even when selecting a non-parametric rule matching mechanism. Grasshopper's ability to handle geometries and text together allows for external descriptions and labels as attributes to points, enabling definition and application of compound, geometric and description rules. Well-known examples from shape grammar literature are implemented using the plug-in, with a focus on rule definition and application in the context of interaction between the parametric modelling environment and the rule-based interpreter, and simultaneous use of geometry, descriptions, and descriptions as attributes in rules.